Reports on the ADI Team Congress 2011
Thursday 14 - Friday 15 April
Manchester Central Convention Complex
Petersfield, Manchester M2 3GX
How learning from past errors can guide the future of dental implants
Speaker: Professor Tomas Albrektsson MD PhD ODhc – Sweden
Reported by Adrian Binney
Peri-implantitis: He went on to use the 1993 definition, which he referenced accurately and carefully, pointing out depending on how you look at peri-implantitis. The different definitions can also define how many implants are affected and it is therefore very important to have a very clear definition about what we consider peri-implantitis to be and how it is measured.
He also pointed out that bone loss is very common and certainly in the Branemark system pointed out that some 1 mm to 2 mm of bone loss over fourteen years would be considered normal and certainly not fall into the category of peri-implantitis. So, initially, a number of studies confused the different features of bone loss around implants. He pointed out that the frequency of implants being effected by peri-implantitis was very dependant on the definition employed.
In the Branemark studies, over 14 years, reported rates of 6.6% were noted and in other studies of 5-20 years 12.4 % were reported. However in certain studies 43% or even up to 85% of implants have been defined as suffering from peri-implantitis. This is obviously not that these implant areas are failing badly but the definition is different.
He went on to outline the difference between teeth and implants and how in certain individuals clearly it can be clustered, i.e. certain individuals are very badly affected. Additionally, the aetiology was discussed. It is very obvious that bacteria is present is in all these peri-implant infected areas. However, it is not known whether bacteria is a secondary invader in an area where the bone losses have occurred or is it primarily causing the bone loss. Several studies have been used to help define this area but Professor Albrektsson noted that these studies do not copy the aetiology and progress of human peri-implantitis. Certainly very good studies have indicated that there is higher incidence of peri-implantitis in patients with previous periodontal disease, but looking at 10 studies, 7 found a correlation and 3 did not find a correlation.
Clinically, also Professor Albrektsson pointed out that pus and bleeding on probing although often seen as a very common clinical sign of peri-implantitis, did not co-relate well with active peri-implantitis and active bone loss. Therefore, clinically it was very difficult to define and diagnose. Additionally, he outlined certain studies that looked at infection and overloading together, but these studies could not bring data which was clinically relevant as there was a significant lack of evidence.
He then went on to compare the healing and adaption theory of the likely cause of bone loss and outlined that poor surgical techniques and surgical skills could cause cell death. Additionally, one of the other big factors would be the host response such as genetics or drugs taken by patients and again these are a major factor. Occlusal forces are also within this theory and indeed smoking, allergies and systemic conditions, all can cause increased bone loss.
With secondary peri-implantitis where implant bacteria has invaded following bone loss, indeed the concern in this area may be that by trying to measure around the implants with pocket probes we infect the area and accelerate the bone loss. This although is not proven.
Following the outline of these different theories and different possibilities with bacteria overloading and host responses, Professor Albrektsson went onto answer the key question of the talk which was how do we learn from the future.
He outlined that bone would stay in position around the implant if the implant is a perfect implant, that surgery is carried out perfectly, the prosthetic is perfect and the patient is perfect. In this situation bone can be guaranteed, but of course we all work in a clinically less than perfect environment and in certain situations if the implant design or surface is incorrect or if the surgery is carried out and the cooling is incorrect or drill sequence has been done incorrectly, prosthetic fit is poor or cement is left then failure or bone loss is inevitable.
He went onto point-out one of the biggest factors in implant success and how to improve it in the future, is to look at ourselves and our clinical treatment. We need to ensure we are not carrying out traumatic surgery and that surgery is carried out in the most atraumatic way possible. He outlined this with good examples that the clinician needs to understand, not only the science, but the art of implant surgery.
He backed these comments up by presenting some long-term studies that were carried out in his university for implants and also for hip surgery. All hip surgery in the area around Professor Albrektsson’s University and implants were logged over many-many years and certain clusterings of failure were noted. These were noted in certain surgeons independent of the type of the patient they treated or the implants they were using. He used this evidence to back up the point that we as clinicians need to understand not only the science, but it is the art of the procedure that equally is important, how we treat bone, how we treat gums and how we respect the biology of the systems.
He also pointed out that implants are a constantly changing design, materials and surfaces and he pointed out that it is absolutely essential that we use systems that have got good clinical documentation with long-term follow up. Professor Albrektsson pointed out that a number of implants have come and have been used extensively, but then since withdrawn. Corvent in 1991 was withdrawn. IMZ was removed in 1997. Nobel Direct had a third of failures of 3 mm resorption or more at a year and his feeling was that it was a good system, but the protocol for this implant was incorrect. The protocol indicated that the implant could be placed and then prepared. He felt that the micro movement and damage to that interface between implant and bone was the cause of this extensive failure of bone loss at a year.
Having outlined in detail, with good humour these points, Professor Albrektsson went onto answer the key question, what do we learn for the future? He pointed out that we should learn:
- Understanding the biology of the system, understanding the art of clinically undertaking these procedures.
- We should understand the healing and adaption of the problem and how bone reacts to it.
- We should take what the companies say and be very critical of it. The ‘do what you’ like philosophy we certainly would not prescribe to it. He emphasised the need for a good long-term follow-up and using systems with very careful and well thought out protocols.
In conclusion, he pointed out that modern implants do appear better than previous designs and certain surfaces and surgical protocols are certainly improved on where we were so many years ago. He speculated where we may go in the future, but our success rates certainly with modern implants he pointed out, when done correctly and with the right art and science can produce excellent results.
He also pointed out that there are a number of patients and failures of unknown reason and certainly this is where we will able to learn for the future.
Professor Albrektsson gave a very balanced and excellent opening to the ADI national conference, explaining a number of different scientific presentations and putting them in context and how we look back at them over the last ten years. It was interesting that with all the science that we have for implants, that one of the strong themes out of his talk, was that we should understand the art of implantology and respect it and learn this is an important factor in success of our patients, something that every clinician I am sure, will understand and recognise.